PU or Epoxy: Which is the best surfboard?

Surfing is a practice that began in the 1960s. This thrill sport of balancing on a board and surfing the waves at sea is particularly popular in areas where the sea is rough and the wind is blowing. In any case, these boards must be designed to withstand sometimes extreme conditions and at the same time provide a good grip for the surfer.

We will see which board material is best suited for surfing.

The manufacturing processes of a surfboard

A surfboard can be made using several techniques, but monolithic construction is the most common form because of its ease and the limited materials it requires.

Here is how manufacturing works:

First of all, it is necessary to obtain a foam bread. The latter is made of polyurethane foam and a wooden slat that splits its middle. Foam bread is the raw material of the board and is what gives the board its rigidity.

The foam bread is then “shapen”, i.e. worked with tools such as a planer or a sander, to give it its final shape (aerodynamic).

Once the board has taken shape, the stratification process comes into play. Lamination consists of laying out resin and fiberglass in several layers to give the board its waterproofness, strength and protection against the sun’s UV rays that can alter the foam. The plugs and boxes are then added to the board. These allow you to change fins at will.

Then comes the application of thicker layers of lamination to solidify the whole thing and facilitate the final steps. This means dry sanding the board, adding a final polyester top coat and then dry sanding again, using water and then polish.

Polyurethane boards

In concrete terms, polyurethane foam is the most commonly used material in surfboard construction. This material is the heart of the board. However, the resin added during lamination can be made of different materials.

We will therefore observe the advantages of using a polyurethane board:

First of all, polyurethane is a low porosity material and therefore presents almost no risk of being filled with water; in case a hole is made in the foam during practice.

Polyurethane foam blends well with polyester resin. The latter is inexpensive, easy to apply and work very easily, since it can withstand ambient temperatures (10 to 25 °), which is not the case for all resins! Its easy polishing also allows a simpler finish.

The foam is easy to work with and requires very little finishing sanding. It also has a very nice appearance once finished. It can therefore be decorated quite easily with a gravity gun, for example.

The polyurethane board has many advantages but also some disadvantages:

For safety reasons, it is necessary to protect yourself with a breathing mask to avoid any risk of dust inhalation due to the “shape” process of the board.

Polyurethane foam has a high density of about 50 kg/m3. This means that precautions must be taken during the stratification stage. Indeed, if the board receives too much resin during the assembly of its layers, it could turn out to be too heavy and no longer be suitable for surfing. Indeed, if it does not respect a certain precision, the board risks losing its floating properties and sinking under the weight of its owner. Finally, this material has a low shape memory. It should be handled with care when it is made, as the slightest impact could cause irreversible visible traces.

Epoxy surfboards

Epoxy is a resin that generally combines with a polystyrene foam base. This packaging is much less common than polyurethane. Indeed, it takes much more time and resources to build a polystyrene and epoxy resin board.

Let’s see the advantages of a polystyrene and epoxy resin board:

Expanded polystyrene, unlike polyurethane, offers a low density generally between 24 and 30 kg/m3. This allows us to obtain a lightweight board ideally designed to receive all the necessary stratification.

The durability of the bread is of high quality. Its shape memory is more than correct and the board is more resistant to the dents and shocks it can receive during its manufacture.

Polystyrene has excellent adhesion to the resin. This allows it to receive the epoxy resin, which has several advantages: excellent adhesion, quality lamination giving even more resistance to impact or pressure, to the entire structure! The resin is applied in a less precipitated manner since it dries more slowly than polyester resin. This is due to the fact that epoxy resin is a two-component material that also has its hardener.

The disadvantages of a polystyrene and epoxy resin board:

Polystyrene is fragile and therefore has more porosity than polyurethane. We must therefore redouble our attention, otherwise we risk having a faulty board.

The raw material and epoxy resin are much more difficult to process. The design process takes longer. Polyurethane also does not accept polyester resin. It is therefore mandatory to purchase epoxy resin, which is more expensive and complex to work with. Indeed, this resin must be processed under optimal conditions: a temperature of 20 ° and a low humidity level, otherwise poor stratification may occur.

Which material to choose?

These two materials are therefore diametrically opposed! Although the most surfboards are made of polyurethane with polyester resin for their ease of construction and accessibility in terms of price, polystyrene and epoxy resin boards also have undeniable advantages!

So how do you make your choice? It’s simply a matter of preferences. The polystyrene and epoxy resin board has a rigidity and lightness that make the difference on the board. Unlike conventional polyurethane boards, it does not absorb the wave and it is up to the surfer to take it (hence its rigidity). However, the board offers unparalleled responsiveness due to its light weight. Thus, it follows the movement of the surfer without difficulty.

PU boards have their qualities and defects but have the undeniable advantages of being cheaper and faster to build. In case of repair, it will also be easier to obtain polyester resin than epoxy.

The two boards are therefore adapted to different surfing styles and surfing styles.